In the area of personal transportation, in particular the lighting system in the equipment comprising the passenger compartment plays an important role with respect to the traveling comfort of passengers. In aircraft technology, the lighting units, such as reading lamps, are usually integrated into a control panel above each passenger seat, the so-called PSU (passenger service unit). The number of PSU's is very high in large aircraft. In particular given a great seating density, it is advantageous to provide compact arrangements to save on space, weight and cost.
The reading lamps are usually separate units, meaning that four to two reading lamps per PSU are installed above the passengers. The different reading lamps are aligned manually on the desired seat depending on the seating configuration. For example, if the class configuration changes during flight operations, the reading lamps must be realigned. The disadvantage to conventional lighting techniques in aircraft is that a variety of lamps, as a rule two to four, are necessary to provide each aircraft passenger with optimal lighting, for example for reading purposes. Combining several reading lamps into a single unit offers both a functional and weight advantage, since the high number of different functional units in the PSU ceiling channel can thereby be reduced. Therefore, it is desirable to find a solution for providing compact lighting units in conjunction with a comfortable and central alignment option.
According to Patent Specification US 2008/0112155, the elements in a PSU can be reduced by integrating a reading lamp into a personal air outlet by arranging an illuminated ring of LED's around the air nozzle. In order to align the ray of light for the individual passenger, the housing can be mechanically turned. While combining the air nozzles with the reading lamps cuts the number of elements to be built into the PSU in half, one lighting unit per passenger is still required.